Fire and heat protection for structural steel has been provided by four major types of systems: cementitious spray coatings, sheet rock framing, intumescent spray coatings and concrete encapsulation. Protection is provided at temperatures up to 2300.degree. F. for periods of one-half hour (1/2 hour) to four hours (4 hrs). Typical structural steel systems requiring such protection include columns, beams and open web joists in houses, buildings, factories and many other types of construction. In addition to land based systems, protection is required for structural steel in off shore drilling platforms, oil and gas pipelines and other marine based systems.
The four basic systems currently used to protect structural steel from fire and heat are described as follows:
1. Cementitious--This spray on material, is a "cement like" fibrous mass of inorganic products combined with water and air to provide adhesion to the steel. It has a relatively high insulation value and heat capacity.
2. Sheet Rock/Framing--The structural steel component is framed typically with wood or metal studs, and one to two layers of gypsum wallboard (sheet rock) installed on the framing.
3. Intumescent--These materials are coatings, sprayed directly on the steel, which expand when exposed to fire. The expansion results in an insulated layer, which provides the fire protection.
4. Concrete--This provides a very large, heavy and high heat capacity mass which "absorbs" much of the incident heat to provide the steel protection.
These techniques have one or more of the following disadvantages associated with their use:
1. Expensive materials.
2. Labor intensive to install, requiring multiple operations, and evacuation of the job site during application.
3. Messy, hazardous and environmentally unfriendly airborne particles and residues.
4. Heavy.
5. Bulky, requiring substantial space.
6. Unattractive appearance, requiring additional decorative treatments.
7. Short lived, requiring removal, reinstallation or loss of fire protection.
In most applications in land based systems, the only important criterion for selection of a fire protection system is cost. Thus in most cases, the fire protection system selected is cementitious spray on fireproofing. However these materials are very messy involving potentially hazardous and environmentally unsafe components, require the evacuation of the job site for long periods of time during application, require substantial clean-up, are very unattractive and inappropriate for structural steel that is normally in plain view. Additionally, they tend to flake off over time causing potentially hazardous airborne particles, exposing unprotected areas on the steel.
Currently there is no single thermal protection wrapping system having all of the following desirable features:
1. Low cost of materials
2. Low cost and simple installation requiring only one step
3. No evacuation of job site required during installation
4. No clean-up required after completion
5. No hazardous or messy components
6. Completely dry installation
7. No environmentally unfriendly materials
8. Lasts indefinitely with no flaking or peeling, requiring no maintenance
9. Attractive appearance, available in many colors and styles
10. Light weight
11. Small size and small "foot print"
12. Easily removable and replaceable for easy access to steel structure when necessary
13. Adaptable to all sizes of columns, beams and open web joists
There remains a need for a new and improved thermal protection system that would provide substantial protection from fire and heat to structural steel columns, beams and joists for a long duration of time if a fire were to occur without adding a large amount to the cost, size, weight and hazards. In addition, the thermal protection system should be easy to install, durable, attractive, easy to remove and adaptable for use on many configurations, types and sizes of columns, beams and open web joists.